By Arjuna Hulugalle
Mahatma Gandhi Centre
S. A. Kulasooriya and Gamini Seneviratne, two eminent Research Professors at the Institute of Fundamental Studies, Kandy said in an interview in Colombo that forethought and foresight is needed on policy related to the use of chemical fertilizers. Possible scenarios in the future have to be anticipated and plans have to be in readiness to meet eventualities as they unfold. "Knee jerk reactions" should be avoided. They are expensive and most often lead to faulty decisions. One should also look for solutions at our doorstep and for local alternatives rather than be influenced by external advice. Commonsense is therefore important in all planning.
Sri Lanka’s chemical fertilizer import bill stands at over USD 29 Million (approximately Rs 33 billion). This figure will escalate with the oil price increase and the worsening situation in the Persian Gulf and also the depreciating rupee.
Apart from the outflow of foreign exchange, the fertilizer subsidy is even higher. The figure for 2010 stood at Rs 65.5 Billion (Source: Daily News May 12, 2011). It is difficult to fathom why basic facts are ignored by policy makers, which will enable the country to cut back on the expenditure on chemical fertilizers. A glaring example is the subsidy on legume pulse crops which are capable of obtaining nitrogen from the air and therefore do not need a government subsidy for nitrogen fertilizers.
Research studies conducted during the past two decades have yielded environmental friendly bio-fertilizers that can minimize the application of imported chemical fertilizers. These local inputs have received no state incentives to popularize their uses and efficacy and to demonstrate the related technologies among the cultivators.
What is particularly worrying with use of chemical fertilizers is that with time degeneration sets in making soils sick and dead. Worst of all, there are very adverse effects to human health and this is becoming more and more evident.
The incidence of cancer and the ‘blue baby’ syndrome has shown a marked increase.
Spread of chemical fertilizers and pesticides since the 1960’s
Years of the extension programs of the Departments of Agriculture and Agrarian Services and the massive advertising done by private sector companies which started with the launch of the ‘green revolution’ in the 1960s have familiarized the use of chemical fertilizers and agro-chemicals even to the remotest of villages.
The two scientists admitted that the high yields obtained from fertilizer responsive new (hybrid) varieties of crops probably prevented food shortages in the past as production levels through traditional methods may not have been able to meet the food demand of an ever increasing non-farming population.
The fact however is that chemical nutrients were added to soils that was under traditional farming. These soils had a build up of organic matter supporting an active population of soil organisms.
Misconception about soil fertility
The two scientists emphasized that there is a widespread misconception that soil fertility is synonymous with chemical nutrients. Soil fertility is the ability of a soil to support sustainable plant growth and this is much more than supplying nutrients. Besides providing a substrate for the plants to anchor themselves, a fertile soil should have optimal levels of air, moisture, and pH, organic matter (that ensure water holding and cation exchange capacities). Also, most importantly, micro and semi-macro soil organisms that perform functions vital for plant growth.
A fertile soil should be like a moist, soft sponge in which plant roots can grow easily, breathe comfortably and actively and efficiently absorb nutrients which are retained in its colloidal organic matrix.
To illustrate this the scientists drew attention to the lush wet zone rainforests like Sinharaja supporting an above ground, visible wide biodiversity, with its species richness. Though we do not see it there is comparable underground diversity which is a vital component that ensures the health of a soil. These living organisms play a crucial role in the sustenance of chemical and physical factors in dynamic equilibrium that contribute to soil fertility. The continuous application of heavy doses of chemical fertilizers and other agro-chemicals kill most of the living organisms in the soil.
Toxins in the water and USD 23 billion ‘washed down the drain’
The scientist highlighted the alarming situation that soils are becoming sick and die as a result of excessive use of chemical fertilizer and pesticides. These soils have low organic matter and little microbial activity. They are unable to retain the nutrients added in the form of soluble chemicals and often less than 30% of the nutrients added are taken up by the targeted crops. The balance 70% is lost.
On an approximate calculation, this means that 23 billion dollars worth of fertilizer imports is ‘washed down the drain’!
What is even more frightening is that these chemicals pollute the environment including our streams, rivers, reservoirs and even domestic wells.
Consumption of such water with high chemical content has dangerous health hazards. Chemical inflows into stagnant water bodies like tanks, ponds, lakes and reservoirs result in eutrophication. This leads to the formation of ‘algal blooms’. A number of these blooms forming cyanobacteria (blue-green algae) produce toxins that contribute to ailments such as liver and kidney failure.
The Institute of Fundamental Studies have recently being doing studies which have confirmed previous reports of the prevalence of toxin producing algae in water bodies of Sri Lanka. The studies have also shown an alarming increase in such populations particularly of Cylindrospermopsis raciborski and Microcystis aerugenosa. This means that on the one hand the government has to spend large sums of money on fertilizer subsidies and on the other hand it has to bear enormous, additional costs for health services as well as water purification.
How can we get out of this situation?
Restore soil health by minimizing the use of agro-chemicals. Bring back the practice of adding organic matter in the form of recycling crop residues, adding animal dung, compost, green manure etc. Depending on the location, type of crop and season, the practices can vary.
Increase in organic matter will automatically bring back the micro and semi-macro living organisms. Unfortunately however, these natural processes require time and this could be a constraint for the realization of large scale production targets of essential food crops like rice, pulses and most vegetables. In other words, it may not be prudent to depend entirely upon organic inputs without any addition of chemical fertilizers.
Organic agriculture alone too expensive
Those who advocate organic agriculture could counter argue this strategy, but up to now organically produced food is costly and a large majority of our population will not be able to afford organically produced food at current prices.
Crop production without any chemical inputs is not the solution and a judicious combination of chemical fertilizer together with organic and/or bio-fertilizers could be the best option.
A step in the right direction
A recent decision taken by the Government to provide fertilizer subsidies only to farmers who apply a certain amount of organic matter to their fields is certainly a step in the right direction. The implementation of this policy should be monitored carefully.
Use of Bio fertilizers tests and the saving of Rs 72 Million already
Novel developments to minimize complete dependence on chemical fertilizers are the use of different types of bio-fertilizers. For leguminous pulse crops, such as soybean, mung bean, cowpea, black gram and ground nut, it is possible to apply rhizobial inoculants.
The Institute of Fundamental Studies (IFS) is continuing a project to prepare and supply such inoculants for soybean at a very low cost of Rs. 300/- a packet that is adequate for an acre of soybean. Use of these inoculants can replace the entire application of urea fertilizer and already some 4,000 to 5,000 acres of soybean is successfully cultivated in this manner (Photo 1). Use of such inoculants is currently saving the country Rs.72 million annually. Research studies to prepare inoculants for mung bean and cowpea are in progress and they should be available in the near future.
Research break-through on Biofilm-biofertilizers
A breakthrough in biofertilizer research came with the development of biofilm-biofertilizers (BFBFs), a technology developed at the IFS for the first time in the scientific world. Biofilm formation has been observed and their potential uses have been reported earlier in international literature. However, the development of biofilm-biofertilizers for targeted crops and the introduction of this term in agriculture are the novel achievements of the Microbial Biotechnology Unit of the IFS.
Biofilms are consortia of different microorganisms such as bacteria, actinobacteria, fungi and cyanobacteria growing together as a community within a common matrix of mucilage. For example, free living rhizobial bacteria do not fix atmospheric nitrogen, neither do fungi fix nitrogen. However, when these two groups are put together and made to form a biofilm some such biofilms are capable of nitrogen fixation in air. This was demonstrated for the first time at the IFS.
BFBFs can replace 50 per cent of chemical fertilizers
The BFBFs developed for tea have been field tested in collaboration with the Tea Research Institute (TRI) during the past six years. Results obtained in the upcountry, mid-country and low country estates show that BFBFs can replace 50% of the chemical fertilizers applied for nursery, young and mature tea without any reduction in the yield of tea. They have also provided convincing evidence that the application of BFBFs also makes the tea plants more resistant to drought, stem borer infestations and increases soil organic carbon which makes these soils more fertile.
Tests with rice, maize, pulse legumes and certain vegetables have also given encouraging results. BFBFs contribute significantly to restore soil health and ameliorate most of the impediments to sustainable agriculture.
The two scientists stated that they would prefer to rename the new input as biofilm-soil ameliorators rather than a fertilizer.
Both scientists felt that the major constraint for the widespread use of these low cost, environmentally benign, indigenous soil ameliorators is the fertilizer subsidy indiscriminately extended by the government to all crops including those capable of fixing their nitrogen from air.
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